The present invention relates to dyeing compositions containing monobenzene nitroanilines having at least one cationic charge delocalized over an unsaturated 5-membered polynitrogenous heterocycle, and comprising at least one cationic group chosen from certain types of aliphatic chains, and to the use of such compositions as direct dyes in dyeing applications for keratinous substances, in particular for human keratinous fibers and especially the hair.
It is known to dye keratinous fibers, and in particular the hair, with dyeing compositions comprising direct dyes, i.e., coloring molecules having an affinity for the fibers. The dyeing process which employs them is a so-called direct coloring process, wherein the direct dyes are allowed to stand on the fibers and are then rinsed.
The colorings which result therefrom are temporary or semi-permanent colorings, because the nature of the interactions which bind the direct dyes to the keratinous fiber and their desorption from the surface and/or from the core of the fiber are responsible for their weak dyeing power and their poor ability to withstand washing operations or perspiration.
Cationic nitroanilines have certainly already been described among known direct dyes but their cationic charge is localized on the nitrogen atom of an aliphatic chain. Such nitroanilines are disclosed, for example, in U.S. Pat. Nos. 5,135,543 and 5,256,823, the disclosures of which are incorporated by
However, in hair dyeing, there is a constant search for direct dyes which exhibit improved characteristics.
It is therefore after a great deal of research directed at this question that the inventors have now just discovered, entirely unexpectedly and surprisingly, that cationic monobenzene nitroanilines with at least one cationic charge delocalized over an unsaturated 5-membered polynitrogenous heterocycle and therefore comprising at least one Z cationic group, Z being chosen from quaternized aliphatic chains, aliphatic chains comprising at least one quaternized saturated ring and aliphatic chains comprising at least one quaternized unsaturated ring, are suitable for use as direct dyes in direct dyeing and, in addition, that they make it possible to obtain dyeing compositions resulting in powerful and varied colorings exhibiting excellent properties of resistance to various attacks which hair may be subject to (light, rubbing, bad weather, shampoos or perspiration) which are significantly improved with respect to those of the colors achieved with known cationic nitroanilines of the prior art, the cationic charge of which is localized on the nitrogen atom of an aliphatic chain.
Finally, these nitroanilines exhibit a better solubility in the media conventionally used for the dyeing of keratinous fibers and prove to be easy to synthesize.
These discoveries form the basis of the present invention.
A subject of the present invention is thus the use, in direct dye compositions or for the manufacture of dyeing compositions for keratinous substances and in particular for human keratinous fibers, such as the hair, of cationic monobenzene nitroanilines of following formula (I) and their acid addition salts: 
in which formula,
R1 and R2, which can be identical or different, represent a hydrogen atom; a Z group defined below; a (C1-C6)alkyl radical; a monohydroxy(C1-C6)alkyl radical; a polyhydroxy(C2-C6)alkyl radical; a (C1-C6)alkoxy(C1-C6)alkyl radical; an aryl radical; a benzyl radical; a cyano(C1-C6)alkyl radical; a carbamyl(C1-C6)alkyl radical; an N-(C1-C6)alkylcarbamyl(C1-C6)alkyl radical; an N,N-di(C1-C6)alkylcarbamyl(C1-C6)alkyl radical; a thiocarbamyl(C1-C6)alkyl radical; a trifluoro(C1-C6)alkyl radical; a sulpho(C1-C6)alkyl radical; a (C1-C6)alkylcarboxy(C1-C6)alkyl radical; a (C1-C6)alkylsulphinyl(C1-C6)alkyl radical; an aminosulphonyl(C1-C6)alkyl radical; an Nxe2x80x94Z-aminosulphonyl(C1-C6)alkyl radical; an N-(C1-C6)alkylaminosulphonyl(C1-C6)alkyl radical; an N,N-di(C1-C6)alkylaminosulphonyl(C1-C6)alkyl radical; a (C1-C6)alkylcarbonyl(C1-C6)alkyl radical; an amino(C1-C6)alkyl radical, the alkyl of which is unsubstituted or substituted by one or more hydroxyl radicals; or an amino(C1-C6)alkyl radical, the alkyl of which is unsubstituted or substituted by one or more hydroxyl radicals and the amine of which is substituted by one or two identical or different radicals which may together form, with the nitrogen atom to which they are attached, a carbonaceous 5- or 6-membered ring or a 5- or 6-membered ring comprising one or more heteroatoms, or which are chosen from alkyl, monohydroxy(C1-C6)alkyl, polyhydroxy(C2-C6)alkyl, (C1-C6)alkylcarbonyl, carbamyl, N-(C1-C6)alkylcarbamyl or N,N-di(C1-C6)alkylcarbamyl, (C1-C6)alkylsulphonyl, formyl, trifluoro(C1-C6)alkylcarbonyl, (C1-C6)alkylcarboxyl or thiocarbamyl radicals, or from a Z group defined below;
R3 and R4, which can be identical or different, represent a hydrogen atom; a halogen atom; a Z group defined below; a (C1-C6)alkylcarbonyl radical; an amino(C1-C6)alkylcarbonyl radical; an Nxe2x80x94Z-amino(C1-C6)alkylcarbonyl radical; an N-(C1-C6)alkylamino(C1-C6)alkylcarbonyl radical; an N,N-di(C1-C6)alkylamino(C1-C6)alkylcarbonyl radical; an amino(C1-C6)alkylcarbonyl(C1-C6)alkyl radical; an Nxe2x80x94Z-amino(C1-C6)alkylcarbonyl(C1-C6)alkyl radical; an N-(C1-C6)alkylamino(C1-C6)alkylcarbonyl(C1-C6)alkyl radical; an N,N-di(C1-C6)alkylamino-(C1-C6)alkylcarbonyl(C1-C6)alkyl radical; a carboxyl radical; a (C1-C6)alkylcarboxyl radical; a (C1-C6)alkylsulphonyl radical; an aminosulphonyl radical; an Nxe2x80x94Z-aminosulphonyl radical; an N-(C1-C6)alkylaminosulphonyl radical; an N,N-di(C1-C6)alkylaminosulphonyl radical; an aminosulphonyl(C1-C6)alkyl radical; an Nxe2x80x94Z-aminosulphonyl(C1-C6)alkyl radical; an N-(C1-C6)alkylaminosulphonyl(C1-C6)alkyl radical; an N,N-di(C1-C6)alkylaminosulphonyl(C1-C6)alkyl radical; a carbamyl radical; an N-(C1-C6)alkylcarbamyl radical; an N,N-di(C1-C6)alkylcarbamyl radical; a carbamyl(C1-C6)alkyl radical; an N-(C1-C6)alkylcarbamyl(C1-C6)alkyl radical; an N,N-di(C1-C6)alkylcarbamyl(C1-C6)alkyl radical; a (C1-C6)alkyl radical; a monohydroxy(C1-C6)alkyl radical; a polyhydroxy(C2-C6)alkyl radical; a (C1-C6)alkoxy(C1-C6)alkyl radical; a trifluoro(C1-C6)alkyl radical; a cyano radical; an OR5 or xe2x80x94SR5 group defined below; or an amino(C1-C6)alkyl radical, the alkyl of which is unsubstituted or substituted by one or more hydroxyl radicals and the amine of which is unsubstituted or substituted by one or two identical or different radicals which may together form, with the nitrogen atom to which they are attached, a carbonaceous 5- or 6-membered ring or a 5- or 6-membered ring comprising one or more heteroatoms, or which are chosen from (C1-C6)alkyl, monohydroxy(C1-C6)alkyl, polyhydroxy(C2-C6)alkyl, (C1-C6)alkylcarbonyl, carbamyl, N-(C1-C6)alkylcarbamyl or N,N-di(C1-C6)alkylcarbamyl, (C1-C6)alkylsulphonyl, formyl, trifluoro(C1-C6)alkylcarbonyl, (C1-C6)alkylcarboxyl or thiocarbamyl radicals, or from a Z group defined below;
R5 denotes a hydrogen atom; a (C1-C6)alkyl radical; a monohydroxy(C1-C6)alkyl radical; a polyhydroxy(C2-C6)alkyl radical; a Z group; a (C1-C6)alkoxy(C1-C6)alkyl radical; an aryl radical; a benzyl radical; a carboxy(C1-C6)alkyl radical; a (C1-C6)alkylcarboxy(C1-C6)alkyl radical; a cyano(C1-C6)alkyl radical; a carbamyl(C1-C6)alkyl radical; an N-(C1-C6)alkylcarbamyl(C1-C6)alkyl radical; an N,N-di(C1-C6)alkylcarbamyl(C1-C6)alkyl radical; a trifluoro(C1-C6)alkyl radical; an aminosulphonyl(C1-C6)alkyl radical; an Nxe2x80x94Z-aminosulphonyl(C1-C6)alkyl radical; an N-(C1-C6)alkylaminosulphonyl(C1-C6)alkyl radical; an N,N-di(C1-C6)alkylaminosulphonyl(C1-C6)alkyl radical; a (C1-C6)alkylsulphinyl(C1-C6)alkyl radical; a (C1-C6)alkylsulphonyl(C1-C6)alkyl radical; a (C1-C6)alkylcarbonyl(C1-C6)alkyl radical; an amino(C1-C6)alkyl radical, the alkyl of which is unsubstituted or substituted by one or more hydroxyl radicals; or an amino(C1-C6)alkyl radical, the alkyl of which is unsubstituted or substituted by one or more hydroxyl radicals and the amine of which is substituted by one or two identical or different radicals which may together form, with the nitrogen atom to which they are attached, a carbonaceous 5- or 6-membered ring or a 5- or 6-membered ring comprising one or more heteroatoms, or which are chosen from (C1-C6)alkyl, monohydroxy(C1-C6)alkyl, polyhydroxy(C2-C6)alkyl, (C1-C6)alkylcarbonyl, formyl, trifluoro(C1-C6)alkylcarbonyl, (C1-C6)alkylcarboxyl, carbamyl, N-(C1-C6)alkylcarbamyl, N,N-di(C1-C6)alkylcarbamyl, thiocarbamyl or (C1-C6)alkylsulphonyl radicals, or from a Z group defined below;
Z is chosen from the unsaturated cationic groups of following formulae (II) and (III) and the saturated cationic groups of following formula (IV): 
xe2x80x83in which:
D is a linking arm which represents a linear or branched alkyl chain preferably comprising from 1 to 14 carbon atoms which can be interrupted by one or more heteroatoms, such as oxygen, sulphur or nitrogen atoms, and which can be substituted by one or more hydroxyl or (C1-C6)alkoxy radicals and which can carry one or more ketone functional groups;
a the E, G, J, L and M vertices, which are identical or different, represent a carbon, oxygen, sulphur or nitrogen atom;
n is an integer ranging from 0 to 4;
m is an integer ranging from 0 to 5;
the R radicals, which are identical or different, represent a second Z group identical to or different from the first Z group; a halogen atom; a hydroxyl radical; a (C1-C6)alkyl radical; a monohydroxy(C1-C6)alkyl radical; a polyhydroxy(C2-C6)alkyl radical; a nitro radical; a cyano radical; a cyano(C1-C6)alkyl radical; a (C1-C6)alkoxy radical; a tri(C1-C6)alkylsilyl(C1-C6)alkyl radical; an amido radical; a formyl radical; a carboxyl radical; a (C1-C6)alkylcarbonyl radical; a thio radical; a thio(C1-C6)alkyl radical; a (C1-C6)alkylthio radical; an amino radical; an amino radical protected by a (C1-C6)alkylcarbonyl, carbamyl or (C1-C6)alkylsulphonyl radical; or an NHRxe2x80x3 or NRxe2x80x3Rxe2x80x2xe2x80x3 group in which Rxe2x80x3 and Rxe2x80x2xe2x80x3, which are identical or different, represent a (C1-C6)alkyl radical, a monohydroxy(C1-C6)alkyl radical or a polyhydroxy(C2-C6)alkyl radical;
R6 represents a (C1-C6)alkyl radical; a monohydroxy(C1-C6)alkyl radical; a polyhydroxy(C2-C6)alkyl radical; a cyano(C1-C6)alkyl radical; a tri(C1-C6)alkylsilyl(C1-C6)alkyl radical; a (C1-C6)alkoxy(C1-C6)alkyl radical; a carbamyl(C1-C6)alkyl radical; a (C1-C6)alkylcarboxy(C1-C6)alkyl radical; a benzyl radical; or a second Z group identical to or different from the first Z group;
R7, R8 and R9, which are identical or different, represent a (C1-C6)alkyl radical; a monohydroxy(C1-C6)alkyl radical; a polyhydroxy(C2-C6)alkyl radical; a (C1-C6)alkoxy(C1-C6)alkyl radical; a cyano(C1-C6)alkyl radical; an aryl radical; a benzyl radical; an amido(C1-C6)alkyl radical; a tri(C1-C6)alkylsilyl(C1-C6)alkyl radical; or an amino(C1-C6)alkyl radical, the amine of which is protected by a (C1-C6)alkylcarbonyl, carbamyl or (C1-C6)alkylsulphonyl radical; two of the R7, R8 and R9 radicals can also together form, with the nitrogen atom to which they are attached, a saturated carbonaceous 5- or 6-membered ring or a saturated 5- or 6-membered ring which can comprise one or more heteroatoms, such as, for example, a pyrrolidine ring, a piperidine ring, a piperazine ring or a morpholine ring, it being possible for the said ring to be substituted or unsubstituted by a halogen atom, a hydroxyl radical, a (C1-C6)alkyl radical, a monohydroxy(C1-C6)alkyl radical, a polyhydroxy(C2-C6)alkyl radical, a nitro radical, a cyano radical, a cyano(C1-C6)alkyl radical, a (C1-C6)alkoxy radical, a tri(C1-C6)alkylsilyl(C1-C6)alkyl radical, an amido radical, a formyl radical, a carboxyl radical, a keto(C1-C6)alkyl radical, a thio radical, a thio(C1-C6)alkyl radical, a (C1-C6)alkylthio radical, an amino radical or an amino radical protected by a (C1-C6)alkylcarbonyl, carbamyl or (C1-C6)alkylsulphonyl radical; one of the R7, R8 and R9 radicals can also represent a second Z group identical to or different from the first Z group;
R10 represents a (C1-C6)alkyl radical; a monohydroxy(C1-C6)alkyl radical; a polyhydroxy(C2-C6)alkyl radical; an aryl radical; a benzyl radical; an amino(C1-C6)alkyl radical; an amino(C1-C6)alkyl radical, the amine of which is protected by a (C1-C6)alkylcarbonyl, carbamyl or (C1-C6)alkylsulphonyl radical; a carboxy(C1-C6)alkyl radical; a cyano(C1-C6)alkyl radical; a carbamyl(C1-C6)alkyl radical; a trifluoro(C1-C6)alkyl radical; a tri(C1-C6)alkylsilyl(C1-C6)alkyl radical; a sulphonamido(C1-C6)alkyl radical; a (C1-C6)alkylcarboxy(C1-C6)alkyl radical; a (C1-C6)alkylsulphinyl(C1-C6)alkyl radical; a (C1-C6)alkylsulphonyl(C1-C6)alkyl radical; a (C1-C6)alkylketo(C1-C6)alkyl radical; an N-(C1-C6)alkylcarbamyl(C1-C6)alkyl radical; or an N-(C1-C6)alkylsulphonamido(C1-C6)alkyl radical;
x and y are integers equal to 0 or 1; with the following conditions:
xe2x80x83in the unsaturated cationic groups of formula (III):
when x=0, the D linking arm is attached to the nitrogen atom,
when x=1, the D linking arm is attached to one of the E, G, J or L vertices,
y can take the value 1 only:
1) when the E, G, J and L vertices simultaneously represent a carbon atom and when the R6 radical is carried by the nitrogen atom of the unsaturated ring; or else
2) when at least one of the E, G, J and L vertices represents a nitrogen atom to which the R6 radical is attached;
xe2x80x83in the unsaturated cationic groups of formula (III):
when x=0, the D linking arm is attached to the nitrogen atom,
when x=1, the D linking arm is attached to one of the E, G, J, L or M vertices,
y can take the value 1 only when at least one of the E, G, J, L and M vertices represents a divalent atom and when the R6 radical is carried by the nitrogen atom of the unsaturated ring;
xe2x80x83in the cationic groups of formula (IV):
when x=0, then the D linking arm is attached to the nitrogen atom carrying the R7 to R9 radicals,
when x=1, then two of the R7 to R9 radicals jointly form, with the nitrogen atom to which they are attached, a saturated 5- or 6-membered ring as defined above and the D linking arm is carried by a carbon atom of the said saturated ring;
Xxe2x88x92 represents a monovalent or divalent anion and is preferably chosen from a halogen atom, such as chlorine, bromine, fluorine or iodine, a hydroxide, a hydrogen sulphate or a (C1-C6)alkyl sulphate, such as, for example, a methyl sulphate or an ethyl sulphate;
xe2x80x83it being understood:
that the number of Z unsaturated cationic groups of formula (II) in which at least one of the E, G, J and L vertices represents a nitrogen atom is at least equal to 1, and
that, when one and only one of the R1 or R2 or R5 radicals denotes a Z group in which the D linking arm represents an alkyl chain comprising a ketone functional group, then the ketone functional group is not directly attached to the nitrogen atom of the NR1R2 group or to the oxygen atom of the OR5 group when R1 or R2 represents OR5.
The alkyl and alkoxy radicals mentioned above in the formulae (I), (II), (III) and (IV) can be linear or branched.
The cationic monobenzene nitroanilines of formula (I) can optionally be salified by strong inorganic acids, such as HCl, HBr or H2SO4, or organic acids, such as acetic, lactic, tartaric, citric or succinic acid.
Mention may in particular be made, among the rings of the Z unsaturated groups of above formula (II), by way of example, of the pyrrole, imidazole, pyrazole, oxazole, thiazole and triazole rings.
Mention may in particular be made, among the rings of the Z unsaturated groups of above formula (III), by way of example, of the pyridine, pyrimidine, pyrazine, oxazine and triazine rings.
Mention may in particular be made, among the cationic monobenzene nitroanilines of above formula (I), of the following compounds:
3-(3-(4,5-dichloro-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
3-(3-(4-chloro-5-methoxy-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
3-(3-(4-chloro-5-methylsulphanyl-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
1,3-dimethyl-2-(3-methylamino-4-nitrophenylsulphanyl)-3H-imidazol-1-ium methyl sulphate,
1-{2-(5-(2-hydroxyethylamino)-2-methyl-4-nitrophenoxy)ethyl}-3-methyl-3H-imidazol-1-ium bromide,
3-(3-(4-methoxy-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate hydrate,
3-{3-(4-(2-hydroxyethoxy)-2-nitrophenylamino)propyl}-1-methyl-3H-imidazol-1-ium methyl sulphate,
3-methyl-1-(2-(4-nitrophenylamino)ethyl)-3H-imidazol-1-ium bromide,
1-methyl-3-(3-(4-nitrophenylamino)propyl)-3H-imidazol-1-ium methyl sulphate,
1-(3-(2-amino-5-nitrophenoxy)propyl)-3-methyl-3H-imidazol-1-ium chloride hydrochloride,
3-(3-(4,5-dichloro-2-nitrophenylamino)propyl)-1-(3-(trimethylsilanyl)propyl)-3H-imidazol-1-ium chloride hydrate,
1-(3-(2-amino-5-nitrophenoxy)propyl)-2-methyl-2H-pyrazol-1-ium bromide,
1-methyl-3-(3-(2-nitrophenylamino)propyl)-3H-imidazol-1-ium methyl sulphate,
1-(3-chloropropyl)-3-(3-(4-nitrophenylamino)propyl)-3H-imidazol-1-ium chloride,
1-(2-hydroxyethyl)-3-(3-(4-nitrophenylamino)propyl)-3H-imidazol-1-ium chloride,
3-(3-(4-benzyloxy-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
3-(3-(2-cyano-4-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
1-methyl-3-(3-(2-methyl-4-nitrophenylamino)propyl)-3H-imidazol-1-ium methyl sulphate,
3-(3-(2-fluoro-4-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
1-(2-(2-methoxy-4-nitrophenylamino)ethyl)-3-methyl-3H-imidazol-1-ium bromide,
3-(3-(3-hydroxy-4-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
3-(3-(2-chloro-4-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
2-methyl-1-(2-(4-nitrophenylamino)ethyl)-2H-pyrazol-1-ium bromide,
1-(3-bromo-2-hydroxypropyl)-3-(3-(4-nitrophenylamino)propyl)-3H-imidazol-1-ium bromide,
1-(3-trimethylammonio-2-hydroxypropyl)-3-(3-(4-nitrophenylamino)propyl)-3H-1-ium dichloride,
diethyl(2-hydroxyethyl)(4-(4-nitrophenylamino)pentyl)ammonium chloride,
3-(3-(4-chloro-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate,
3-(3-(2-chloro-6-nitrophenylamino)propyl)-l -methyl-3H-imidazol-1-ium methyl sulphate,
1-methyl-3-(2-(4-nitrophenylamino)butyl)-3H-imidazol-1-ium chloride,
3-methyl-1-(2-methyl-2-(4-nitrophenylamino)propyl)-3H-imidazol-1-ium chloride,
1-{2-((2-(3-methyl-3H-imidazol-1-io)ethyl)(4-nitrophenyl)amino)ethyl}-3-methyl-3H-imidazol-1-ium dichloride,
and, more preferably among these, the compounds of following formulae (I)1 to (I)11 are chosen: 
i.e., 3-(3-(4-chloro-5-methoxy-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate, 
i.e., 3-(3-(4,5-dichloro-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate, 
i.e., 3-(3-(4-chloro-5-methylsulphanyl-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate, 
i.e., 3-(3-(4-methoxy-2-nitrophenylamino)propyl)-1-methyl-3H-imidazol-1-ium methyl sulphate hydrate, 
i.e., 1,3-dimethyl-2-(3-methylamino-4-nitrophenylsulphanyl)-3H-imidazol-1-ium methyl sulphate, 
i.e., 1-{2-(5-(2-hydroxyethylamino)-2-methyl-4-nitrophenoxy)ethyl}-3-methyl-3H-imidazol-1-ium bromide, 
i.e., 3-{3-(4-(2-hydroxyethoxy)-2-nitrophenylamino)propyl}-1-methyl-3H-imidazol-1-ium methyl sulphate, 
i.e., 3-methyl-1-(2-(4-nitrophenylamino)ethyl)-3H-imidazol-1-ium bromide, 
i.e., 1-methyl-3-(3-(4-nitrophenylamino)propyl)-3H-imidazol-1-ium methyl sulphate, 
i.e., 1-(3-(2-amino-5-nitrophenoxy)propyl)-3-methyl-3H-imidazol-1-ium chloride hydrochloride, 
i.e., 3-(3-(4,5-dichloro-2-nitrophenylamino)propyl)-1-(3-(trimethylsilanyl)propyl)-3H-imidazol-1-ium chloride hydrate.
The cationic monobenzene nitroanilines of formula (I) in accordance with the invention can be easily obtained according to methods generally well known in the state of the art for the preparation of quaternized amines, for example:
in one step, by condensation of a nitroaniline comprising a haloalkyl radical with a compound carrying a tertiary amine radical or by condensation of a nitroaniline comprising a tertiary amine radical with a compound carrying a haloalkyl radical;
or, in two steps, by condensation of a nitroaniline comprising a haloalkyl radical with a compound carrying a secondary amine or by condensation of an ortho- or para-halonitrobenzene with a (disubstituted amino)alkylamine, followed by quaternization with an alkylating agent.
The quaternization stage is generally, for convenience, the final stage of the synthesis but can take place earlier in the sequence of reactions resulting in the preparation of the compounds of formula (I).
Another subject of the invention is a dyeing composition for keratinous substances, characterized in that it comprises, in a medium appropriate for dyeing, an effective amount of at least one cationic monobenzene nitroaniline of formula (I) described above.
Another subject of the invention is a composition for the direct dyeing of human keratinous fibers, such as the hair, characterized in that it comprises, in a medium appropriate for dyeing, an effective amount of at least one cationic monobenzene nitroaniline as defined above by the formula (I).
Another subject of the invention is the use of the cationic monobenzene nitroanilines of formula (I) as direct dyes in or for the preparation of dyeing compositions for keratinous substances.
However, other characteristics, aspects and advantages of the invention will become even more clearly apparent on reading the description which will follow and various concrete but in no way limiting examples intended to illustrate it.
The cationic monobenzene nitroaniline(s) of formula (I) in accordance with the invention and/or their addition salts with an acid preferably represent from 0.005 to 12% by weight approximately of the total weight of the dyeing composition and more preferably still from 0.05 to 6% by weight approximately of this weight.
The cationic monobenzene nitroanilines of formula (I) can also be used, in the well known processes for oxidation dyeing using oxidation dyes (oxidation dye precursors and, optionally, couplers), to shade or enrich with highlights the colors obtained with the oxidation dyes.
The dyeing composition according to the invention can also comprise, in order to widen the palette of shades and to obtain varied hues, in addition to the cationic monobenzene nitroanilines of formula (I), other direct dye(s) conventionally used and in particular nitrobenzene dyes other than the cationic monobenzene nitroanilines of formula (I) according to the present invention, such as nitrophenylenediamines, nitrodiphenylamines, nitrophenol ethers or nitrophenols, nitropyridines, anthraquinone dyes, mono- or diazo, triarylmethane, azine, acridine and xanthene dyes, or metal complex dyes.
The proportion of all these other additional direct dyes can vary from approximately 0.05 to 10% by weight with respect to the total weight of the dyeing composition.
The medium appropriate for dyeing (or vehicle) is generally composed of water or of a mixture of water and of at least one organic solvent, in order to dissolve the compounds which would not be sufficiently soluble in water. Mention may be made, for example, as organic solvent, of lower C1-C4 alkanols, such as ethanol and isopropanol, glycerol, glycols and glycol ethers, such as 2-butoxyethanol, propylene glycol or propylene glycol monomethyl ether, and aromatic alcohols, such as benzyl alcohol or phenoxyethanol, the analogous products and their mixtures.
The solvents can be present in proportions preferably ranging from 1 to 40% by weight with respect to the total weight of the dyeing composition and more preferably still from 5 to 30% by weight approximately.
Fatty amides, such as the mono- and diethanolamides of the acids derived from copra, of lauric acid or of oleic acid, can also be added to the composition according to the invention at concentrations ranging from approximately 0.05 to 10% by weight.
Surface-active agents well known in the state of the art and of anionic, cationic, nonionic, amphoteric or zwitterionic type or their mixtures can also be added to the composition according to the invention, preferably in a proportion ranging from approximately 0.1 to 50% by weight and advantageously from approximately 1 to 20% by weight with respect to the total weight of the composition.
Thickening agents can also be used in a proportion ranging from approximately 0.2 to 5%.
The dyeing composition can additionally comprise various conventional adjuvants, such as antioxidizing agents, fragrances, sequestering agents, dispersing agents, hair conditioning agents, preserving agents, opacifying agents and any other adjuvant commonly used in dyeing keratinous substances.
Of course, a person skilled in the art will take care to choose the optional additional compound or compounds mentioned above so that the advantageous properties intrinsically attached to the dyeing composition according to the invention are not, or not substantially, detrimentally affected by the envisaged addition or additions.
The dyeing composition according to the invention can be formulated at acidic, neutral or alkaline pH, it being possible for the pH to vary from 3 to 12 approximately and preferably from 5 to 11 approximately. It can be adjusted to the desired value by means of acidifying or basifying agents or of buffers commonly used in dyeing keratinous substances.
The acidifying agents are conventionally inorganic or organic acids, such as, for example, hydrochloric acid, orthophosphoric acid or sulphuric acid, carboxylic acids, such as acetic acid, tartaric acid, citric acid or lactic acid, and sulphonic acids.
Mention may be made, among buffers, of, for example, potassium dihydrogen phosphate/sodium hydroxide.
Mention may be made, among basifying agents, by way of example, of aqueous ammonia, alkaline carbonates, alkanolamines, such as mono-, di- and triethanolamines, and their derivatives, sodium hydroxide, potassium hydroxide and the compounds of formula: 
in which W is a propylene residue optionally substituted by a hydroxyl group or a (C1-C4)alkyl radical and R11, R12, R13 and R14, simultaneously or independently of one another, represent a hydrogen atom or a (C1-C6)alkyl or hydroxy(C1-C6)alkyl radical.
The composition applied to the hair can be provided in various forms, such as in the form of a liquid, cream or gel or in any other form appropriate for carrying out dyeing of keratinous substances. In particular, it can be packaged under pressure in an aerosol can in the presence of a propellant and can form a foam.
Another subject-matter of the present invention is a process for dyeing keratinous fibers, in particular human keratinous fibers, such as the hair, by direct coloring, which comprises the step of allowing a dyeing composition comprising at least one cationic monobenzene nitroaniline of formula (I) to act on dry or wet keratinous fibers. The composition according to the invention can be used as a leave-in composition, that is to say that, after application of the composition to the fibers, drying is carried out without intermediate rinsing.
In the other applicational methods, the composition is allowed to act on the fibers for an exposure time varying from 3 to 60 minutes approximately, preferably from 5 to 45 minutes approximately, rinsing is carried out, washing is optionally carried out, rinsing is then again carried out, and drying is carried out.